Nucleus accumbens

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Nucleus accumbens (red) and ventral tegmental area (VTA, blue)

The nucleus accumbens ( Ncl. Acc .; From Latin nucleus 'core', v. Latin accumbere 'lie down', 'take a seat', 'be present') is a core structure in the lower ( basal ) forebrain , which is in the abdominal ( ventral ) Part of the basal ganglia forms the junction between the putamen and the caudate nucleus (the two components of the corpus striatum ). It consists of a shell region ("shell") and a core region ("core"). The nucleus accumbens plays a central role in the mesolimbic system , the “reward system” of the brain , as well as in the development of addiction .

The mesolimbic system promotes the reinforcement of certain behavior patterns that are related to reward through feelings of happiness. This is particularly interesting when researching addiction to gambling and extreme sports , where the outcome has a certain uncertainty factor and thus a special thrill or stimulus .

anatomy

The mesolimbic system refers to the direct and indirect dopaminergic projections of the ventral tegmental area in

function

In the nucleus accumbens there are dopamine receptors of type D2 , the stimulation of which by the dopaminergic afferents of the ventral tegmental area is assigned to the expectation of a feeling of happiness (“wanting”, in contrast to the feeling of happiness itself, “liking”). Many intoxicating drugs work by directly or indirectly influencing this synaptic transmission, such as amphetamine , cocaine , opiates , tetrahydrocannabinol (THC), phencyclidine and ketamine .

However, the stimulation of the neurons of the ventral tegmental area in the midbrain is also the target of various active substances. The GABAergic interneurons, which have an inhibitory effect on the dopaminergic neurons of the ventral tegmental area , in turn have µ 1 -type opioid receptors . By inhibiting the inhibitory GABAergic interneurons, opioids lead to a disinhibition of the neurons in the ventral tegmental area, which in turn release more dopamine. Thus, opioids sensitize the mesolimbic system for stimulation. Also, ethanol , barbiturates , benzodiazepines and nicotine have a stimulatory or anxiolytic effect on the dopaminergic neurons of the ventral tegmental area.

The nucleus accumbens in turn projects from the shell region over the medial forebrain bundle into the rest of the limbic system and the hypothalamus . The former is involved in cognitive and psychological processing, the latter plays a role in the vegetative response to the feeling of happiness.

Medical importance

Several smaller studies over a period of around 10 years have shown that deep brain stimulation of the nucleus accumbens in severe therapy-resistant depression may be a promising future therapy concept.

The application of deep brain stimulation in the area of ​​the nucleus accumbens leads in the majority of cases to a significant alleviation of symptoms in patients with otherwise therapy-resistant obsessive-compulsive disorder .

See also

literature

Web links

Individual evidence

  1. ↑ GC Quintero Garzola: Review: brain neurobiology of gambling disorder based on rodent models. In: Neuropsychiatric disease and treatment. Volume 15, 2019, pp. 1751-1770, doi : 10.2147 / NDT.S192746 , PMID 31308669 , PMC 6612953 (free full text) (review).
  2. ^ A. Weinstein, Y. Weinstein: Exercise addiction diagnosis, bio-psychological mechanisms and treatment issues. In: Current pharmaceutical design. Volume 20, number 25, 2014, pp. 4062-4069, doi : 10.2174 / 13816128113199990614 , PMID 24001300 (review), PDF .
  3. ^ MD Roberts, GN Ruegsegger, JD Brown, FW Booth: Mechanisms Associated With Physical Activity Behavior: Insights From Rodent Experiments. In: Exercise and sport sciences reviews. Volume 45, number 4, 10 2017, pp. 217-222, doi : 10.1249 / JES.0000000000000124 , PMID 28704221 (review).
  4. ↑ a b Ralf Brandes u. a. (Ed.): Human physiology: with pathophysiology . Springer, Berlin Heidelberg, 2019, ISBN 978-3-662-56468-4 , pp. 857-861, OCLC 1104934728 . , Preview Google Books .
  5. ↑ C. Nauczyciel, S. Robic, T. Dondaine, M. Verin, G. Robert, D. Drapier, F. Naudet, B. Millet: The nucleus accumbens: a target for deep brain stimulation in resistant major depressive disorder. In: Journal of molecular psychiatry. Volume 1, 2013, p. 17, doi : 10.1186 / 2049-9256-1-17 , PMID 26019865 , PMC 4445576 (free full text) (review).
  6. ↑ TE Schlaepfer, BH Bewernick, S. Kayser, R. Hurlemann, VA Coenen: Deep brain stimulation of the human reward system for major depression-rational outcomes and outlook. In: Neuropsychopharmacology . Volume 39, number 6, May 2014, pp. 1303-1314, doi : 10.1038 / npp.2014.28 , PMID 24513970 , PMC 3988559 (free full text) (review).
  7. ↑ P. Vicheva, M. Butler, P. Shotbolt: Deep brain stimulation for obsessive-compulsive disorder: A systematic review of randomized controlled trials. In: Neuroscience and biobehavioral reviews. Volume 109, February 2020, pp. 129-138, doi : 10.1016 / j.neubiorev.2020.01.007 , PMID 31923474 (review).
  8. ^ YS Park, F. Sammartino, NA Young, J. Corrigan, V. Krishna, AR Rezai: Anatomic Review of the Ventral Capsule / Ventral Striatum and the Nucleus Accumbens to Guide Target Selection for Deep Brain Stimulation for Obsessive-Compulsive Disorder. In: World Neurosurgery . Volume 126, 06 2019, pp. 1–10, doi : 10.1016 / j.wneu.2019.01.254 , PMID 30790738 (Review).